Pressurized liquid extraction for the simultaneous analysis of polychlorinated biphenyls and polybrominated diphenyl ethers from soil by GC-TOF-MS detection.

Pressurized liquid extraction (PLE) system was optimized to simultaneously determine polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in soil samples by gas chromatography with time-of-flight mass spectrometry. PLE parameters (temperature, pressure, static time, and flush volume) and packing materials (activated copper and sorbents such as: Florisil, silica gel, and a combination of Florisil and silica gel) were studied to achieve a one-step extraction and cleanup that could be analytically rapid and reliable. Method detection limit was found to be in the range of 0.1-0.4 mg/kg for PCBs and 0.1-0.6 mg/kg for PBDEs with a relative standard deviation of 1.7-7.3% for PCBs and 2.6-6.3% for PBDEs. A standard reference material for PCBs, NIST-SRM 1939a, spiked with PBDEs standard, was analyzed to substantiate the validity of the optimized method. Experimental values agreed well with the certified values with recoveries of 71.6-117%, and the optimized PLE system has been proven to be useful for the simultaneous determination of PCBs and PBDEs with various congeners in soil samples.